A star of one of television's top sitcoms, Kaley Cuoco is hoping to make a big bang in the movies, too.

The young actress's career has been centered on the home screen, thanks to regular roles on "8 Simple Rules" (still seen in repeats on ABC Family), "Charmed" (now rerun weekdays by TNT) and her biggest hit to date: CBS'"The Big Bang Theory," which is holding its own admirably Thursdays against Fox's ratings juggernaut "American Idol."

("Big Bang" is pre-empted this week by coverage of the NCAA Men's Division I Basketball Tournament.)As Easter approaches, though, Cuoco is making a timely leap to the big screen. She's in the cast of "Hop," a fantasy-comedy arriving in theaters April 1. Courtesy of computer animation, she gets to appear opposite the son of the Easter Bunny (sporting the voice of Russell Brand), who travels to Hollywood and is hit by a car ... then is taken in by the driver (James Marsden) and his sister (Cuoco).

"I'm so excited," the lively Cuoco says about the movie's imminent opening as she takes a break from a photo shoot for the CBS-published celebrity magazine Watch! in Berkshire, England. "You get very spoiled when you're on a TV show, so every time my summers came around, I didn't want to do anything. I wanted to hang out with my horses and call people back; I didn't want to work on anything, because I knew I had a job.

"Last summer, I was ready to do a film, and this one came along. It was just the most fun experience. I've really got the film bug now, and I hope that takes me somewhere in my life as well. I'd never say this for sure, but I think I've built a name in television, and my next step is to find a place in the film world. There are all these goals I have, and I've met my television goal, so I want to reach some others."

Indeed, Cuoco has several other film projects in various stages. She also has completed "The Last Ride," a drama about the final days of country music legend Hank Williams (played by Henry Thomas).

Even with those plans, Cuoco will be giving much more "Big Bang" for her bucks. CBS already has renewed the show for not just one more season but three; also, repeats start a weekday run this fall on TBS and local stations, where the series has set an off-network syndication record by netting more than $2 million per episode for Warner Bros. Television.

"The show has done miraculous things for me," Cuoco reflects, adding her belief that she's been professionally lucky in general. "I've grown up in front of the camera. I've worked really hard for 20 years, and it blows my mind when I think about being in this business that long.

"I've learned not to take anything for granted, and I don't know how I landed a show that is this successful. That's super-rare, so I'm riding this wave as long as I can. I didn't see this coming. I have no idea where life will take me next."

Cuoco knows her immediate future, at least, and she embraces continuing to play neighbor Penny to engaging geeks Leonard and Sheldon (Johnny Galecki and Emmy and Golden Globe winner Jim Parsons). She recalls being stunned by the news of the series' virtually unheard-of three-year renewal when she spotted it online while on the show's set.

"We were rehearsing, and I said, 'Hey, guys. Did we get picked up for three years?' Johnny was like, 'Oh, yeah. I heard that.' Then, Jim said, 'Oh, yeah. I heard that, too.' Then we just went on with our day. That's how casual we are at work. Later in the day, we did a big 'Cheers!' over it. That just doesn't happen, to know you have a job for three more years. It's very emotional for me."

Stressing that she's not as casual as she first might appear about such milestones, Cuoco attributes it to "my work ethic. I think some people think it means I don't care, but the more people get to know me and the longer I work with them, they realize that's just kind of the way I am. I'm as happy and grateful as the next person, but I don't take it too seriously."

To see how quickly Cuoco can get serious, though, mention last fall's horse-riding accident that left her with a broken leg and sidelined her from two "Big Bang" episodes.

"I couldn't leave the hospital bed for two weeks," she says, tearing up at the memory. "I was like, 'Have I ruined the show?' After one week, (the doctors) said, 'You can go back and shoot if you want, then come back' -- so I called (executive producers) Chuck Lorre and Bill Prady and said, 'I can do the next episode. Write me something.' The next day, they called back and said, 'It's not anything about you.' They couldn't find a place to put Penny in, and I was so devastated.

"By the next taping, I'd been released from the hospital, and I just came for the curtain call to talk to the audience and thank the writers. I realized, at that moment, that I never wanted to be away from there again. Even now, I cry at every curtain call, because my leg was so badly affected that they didn't know if I would walk again. I am severely, severely grateful."